1. Field
The following description relates to a refrigerator to efficiently cool a plurality of storage chambers and a method of controlling the same.
2. Description of the Related Art
A refrigerator is an apparatus to keep stored objects such as food and beverages fresh for a long time.
The refrigerator has a plurality of storage chambers including a freezing chamber to keep stored objects in a frozen state and a refrigerating chamber to keep stored objects in a refrigerated state. The refrigerator maintains chamber temperatures in the freezing and refrigerating chambers at respective set target temperatures by repeatedly performing a refrigeration cycle consisting of compression, condensation, expansion, and evaporation of a refrigerant.
Such a refrigerator is equipped with a compressor, condenser, expansion valve (or a capillary tube), and evaporator, for example, to perform the refrigeration cycle consisting of compression, condensation, expansion, and evaporation.
To be specific, the refrigerator maintains chamber temperatures in the freezing and refrigerating chambers at respective target temperatures by driving, based on the respective set target temperatures of the freezing and refrigerating chambers, at least one fan installed in each of the freezing and refrigerating chambers so that heat exchanged air at an evaporator is blown into the storage chambers associated with each fan.
However, since such a refrigerator must maintain the chamber temperatures in the freezing and refrigerating chambers at the respective target temperatures using a single evaporator, the refrigerator may not provide a suitable cooling environment as desired by a user.
For this reason, a refrigerator has recently been developed wherein each of the freezing and refrigerating chambers is provided with an evaporator and expansion valve. This refrigerator maintains chamber temperatures in the freezing and refrigerating chambers at a freezing temperature and refrigerating temperature, respectively, by adjusting an amount of refrigerant supplied from the compressor into the respective evaporators via control of the respective expansion valves.
Moreover, in consideration of a great difference between the chamber target temperatures in the freezing and refrigerating chambers, a refrigerator has recently been developed which has freezing and refrigerating compressors having different refrigeration capacities. Such a refrigerator maintains the chamber temperatures in the freezing and refrigerating chambers at respective target temperatures by controlling operations of the associated compressors based on the respective target temperatures in the freezing and refrigerating chambers.
This type of refrigerating compressor has a refrigeration capacity as small as approximately 6/10 of that of an existing compressor, in order to increase an evaporation temperature in the refrigeration cycle to cool the refrigerating chamber.
In other words, the refrigerator further includes a small compressor with a smaller refrigeration capacity in order to increase the evaporation temperature in the refrigeration cycle to cool the refrigerating chamber.
Because a smaller compressor has a suction valve with a lower suction rate of refrigerant due to its smaller size, and operation of the valve is also inefficient compared to a large compressor, mechanical and volumetric efficiencies thereof are lower than those of a large compressor with a large cylinder.
That is, the smaller the compressor size, the smaller the stroke volume, and thus the larger the mechanical loss and volume loss. Therefore, as the stroke volume is reduced, compressor efficiency is greatly lowered, thereby causing a reduction in the effectiveness of the refrigeration cycle.